/*
** Nofrendo (c) 1998-2000 Matthew Conte (matt@conte.com)
**
**
** This program is free software; you can redistribute it and/or
** modify it under the terms of version 2 of the GNU Library General
** Public License as published by the Free Software Foundation.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
** Library General Public License for more details.  To obtain a
** copy of the GNU Library General Public License, write to the Free
** Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
**
** Any permitted reproduction of these routines, in whole or in part,
** must bear this legend.
**
**
** map18.c
**
** mapper 18 interface
** $Id: map018.c,v 1.2 2001/04/27 14:37:11 neil Exp $
*/

#include <noftypes.h>
#include <nes_mmc.h>
#include <nes_ppu.h>

/* mapper 18: Jaleco SS8806 */
#define VRC_PBANK(bank, value, high)                                                                                           \
    do                                                                                                                         \
    {                                                                                                                          \
        if ((high))                                                                                                            \
            highprgnybbles[(bank)] = (value)&0x0F;                                                                             \
        else                                                                                                                   \
            lowprgnybbles[(bank)] = (value)&0x0F;                                                                              \
        mmc_bankrom(8, 0x8000 + ((bank) << 13), (highprgnybbles[(bank)] << 4) + lowprgnybbles[(bank)]);                        \
    } while (0)

#define VRC_VBANK(bank, value, high)                                                                                           \
    {                                                                                                                          \
        if ((high))                                                                                                            \
            highnybbles[(bank)] = (value)&0x0F;                                                                                \
        else                                                                                                                   \
            lownybbles[(bank)] = (value)&0x0F;                                                                                 \
        mmc_bankvrom(1, (bank) << 10, (highnybbles[(bank)] << 4) + lownybbles[(bank)]);                                        \
    }

static struct
{
    int counter, enabled;
    uint8 nybbles[4];
    int clockticks;
} irq;

static void map18_init(void) { irq.counter = irq.enabled = 0; }

static uint8 lownybbles[8];
static uint8 highnybbles[8];
static uint8 lowprgnybbles[3];
static uint8 highprgnybbles[3];

static void map18_write(uint32 address, uint8 value)
{
    switch (address)
    {
    case 0x8000:
        VRC_PBANK(0, value, 0);
        break;
    case 0x8001:
        VRC_PBANK(0, value, 1);
        break;
    case 0x8002:
        VRC_PBANK(1, value, 0);
        break;
    case 0x8003:
        VRC_PBANK(1, value, 1);
        break;
    case 0x9000:
        VRC_PBANK(2, value, 0);
        break;
    case 0x9001:
        VRC_PBANK(2, value, 1);
        break;
    case 0xA000:
        VRC_VBANK(0, value, 0);
        break;
    case 0xA001:
        VRC_VBANK(0, value, 1);
        break;
    case 0xA002:
        VRC_VBANK(1, value, 0);
        break;
    case 0xA003:
        VRC_VBANK(1, value, 1);
        break;
    case 0xB000:
        VRC_VBANK(2, value, 0);
        break;
    case 0xB001:
        VRC_VBANK(2, value, 1);
        break;
    case 0xB002:
        VRC_VBANK(3, value, 0);
        break;
    case 0xB003:
        VRC_VBANK(3, value, 1);
        break;
    case 0xC000:
        VRC_VBANK(4, value, 0);
        break;
    case 0xC001:
        VRC_VBANK(4, value, 1);
        break;
    case 0xC002:
        VRC_VBANK(5, value, 0);
        break;
    case 0xC003:
        VRC_VBANK(5, value, 1);
        break;
    case 0xD000:
        VRC_VBANK(6, value, 0);
        break;
    case 0xD001:
        VRC_VBANK(6, value, 1);
        break;
    case 0xD002:
        VRC_VBANK(7, value, 0);
        break;
    case 0xD003:
        VRC_VBANK(7, value, 1);
        break;
    case 0xE000:
        irq.nybbles[0] = value & 0x0F;
        irq.clockticks = (irq.nybbles[0]) | (irq.nybbles[1] << 4) | (irq.nybbles[2] << 8) | (irq.nybbles[3] << 12);
        irq.counter = (uint8)(irq.clockticks / 114);
        if (irq.counter > 15)
            irq.counter -= 16;
        break;
    case 0xE001:
        irq.nybbles[1] = value & 0x0F;
        irq.clockticks = (irq.nybbles[0]) | (irq.nybbles[1] << 4) | (irq.nybbles[2] << 8) | (irq.nybbles[3] << 12);
        irq.counter = (uint8)(irq.clockticks / 114);
        if (irq.counter > 15)
            irq.counter -= 16;
        break;
    case 0xE002:
        irq.nybbles[2] = value & 0x0F;
        irq.clockticks = (irq.nybbles[0]) | (irq.nybbles[1] << 4) | (irq.nybbles[2] << 8) | (irq.nybbles[3] << 12);
        irq.counter = (uint8)(irq.clockticks / 114);
        if (irq.counter > 15)
            irq.counter -= 16;
        break;
    case 0xE003:
        irq.nybbles[3] = value & 0x0F;
        irq.clockticks = (irq.nybbles[0]) | (irq.nybbles[1] << 4) | (irq.nybbles[2] << 8) | (irq.nybbles[3] << 12);
        irq.counter = (uint8)(irq.clockticks / 114);
        if (irq.counter > 15)
            irq.counter -= 16;
        break;
    case 0xF000:
        if (value & 0x01)
            irq.enabled = true;
        break;
    case 0xF001:
        irq.enabled = value & 0x01;
        break;
    case 0xF002:
        switch (value & 0x03)
        {
        case 0:
            ppu_mirror(0, 0, 1, 1);
            break;
        case 1:
            ppu_mirror(0, 1, 0, 1);
            break;
        case 2:
            ppu_mirror(1, 1, 1, 1);
            break;
        case 3:
            ppu_mirror(1, 1, 1, 1);
            break; // should this be zero?
        default:
            break;
        }
        break;
    default:
        break;
    }
}

static map_memwrite map18_memwrite[] = {{0x8000, 0xFFFF, map18_write}, {-1, -1, NULL}};

static void map18_getstate(SnssMapperBlock* state)
{
    state->extraData.mapper18.irqCounterLowByte = irq.counter & 0xFF;
    state->extraData.mapper18.irqCounterHighByte = irq.counter >> 8;
    state->extraData.mapper18.irqCounterEnabled = irq.enabled;
}

static void map18_setstate(SnssMapperBlock* state)
{
    irq.counter = (state->extraData.mapper18.irqCounterHighByte << 8) | state->extraData.mapper18.irqCounterLowByte;
    irq.enabled = state->extraData.mapper18.irqCounterEnabled;
}

mapintf_t map18_intf = {
    18,              /* mapper number */
    "Jaleco SS8806", /* mapper name */
    map18_init,      /* init routine */
    NULL,            /* vblank callback */
    NULL,            /* hblank callback */
    map18_getstate,  /* get state (snss) */
    map18_setstate,  /* set state (snss) */
    NULL,            /* memory read structure */
    map18_memwrite,  /* memory write structure */
    NULL             /* external sound device */
};

/*
** $Log: map018.c,v $
** Revision 1.2  2001/04/27 14:37:11  neil
** wheeee
**
** Revision 1.1  2001/04/27 12:54:40  neil
** blah
**
** Revision 1.1.1.1  2001/04/27 07:03:54  neil
** initial
**
** Revision 1.1  2000/10/24 12:19:33  matt
** changed directory structure
**
** Revision 1.8  2000/10/22 19:17:46  matt
** mapper cleanups galore
**
** Revision 1.7  2000/10/22 15:03:13  matt
** simplified mirroring
**
** Revision 1.6  2000/10/21 19:33:38  matt
** many more cleanups
**
** Revision 1.5  2000/10/10 13:58:17  matt
** stroustrup squeezing his way in the door
**
** Revision 1.4  2000/07/15 23:52:19  matt
** rounded out a bunch more mapper interfaces
**
** Revision 1.3  2000/07/10 05:29:03  matt
** cleaned up some mirroring issues
**
** Revision 1.2  2000/07/06 02:48:42  matt
** clearly labelled structure members
**
** Revision 1.1  2000/07/06 01:01:56  matt
** initial revision
**
*/
